<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <style>
        .clicky{
            width:100px;
            height: 100px;
            background:#666;
        }
    </style>
</head>
<body>
    <div class="clicky">clicky</div>
    <script src="js/jquery-3.1.1.js"></script>
    <script src="js/class.js"></script>
</body>
</html>